Implantable housing assembly

ABSTRACT

Embodiments of the present invention relate to an implantable device housing assembly, for use in, for example, implantable prosthetic devices. In one aspect, the present invention provides a housing for an implantable device comprising a body portion and a sealing flange. The body portion includes a cavity in which electronic components are disposed on an open side thereof, and at least one feed-through which provides electrical connections between the electronic components and the exterior of the device. The feed-through includes interior and exterior connection points, which are accessible during assembly of the device from a first side of the device. The sealing flange operatively seals the cavity so as to form a sealed housing. A method of forming a sealed housing for an implantable device is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 USC §371 (c)of PCT Application No. PCT/AU2008/000973, entitled “IMPLANTABLE HOUSINGASSEMBLY,” filed on Jul. 2, 2008, which claims priority from AustralianPatent Application No. 2007903542, filed on Jul. 2, 2007 and claimspriority from Australian Patent Application No. 2007903541, filed onJul. 2, 2007 and claims priority from Australian Patent Application No.2008900018, filed on Jan. 3, 2008. The entire disclosure and contents ofthe above applications are hereby incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to implantable medical devices,and more particularly to, a housing for an implantable medical device.

2. Related Art

Devices are implanted in the body of a recipient for a variety ofpurposes including monitoring, heart defibrillation, drug delivery andas neural and organ prostheses. Such implantable devices generallyinclude electronic components and other functional elements configuredfor a variety of purposes, including delivery of electrical stimulationor drugs, monitoring of parameters, communication with, or control of,other devices to store information, and communication via RF or othermeans.

Housing assemblies for implantable devices are required to behermetically sealed and impervious to bodily fluids. This protects therecipient from any interactions with non-biocompatible materials used inthe construction of the components housed inside the housing assembly,and from other adverse interactions with the sealed components. Thehousing also protects the functional components of the device frombodily fluids which could cause electrical short-circuits or otherwiselead to failure of the device.

Certain devices require one or more electrical connections between theinterior of a device housing and elements exterior to the devicehousing. Hermetic enclosures for such devices are constructed frombiocompatible materials, such as titanium or ceramic, and include afeed-through component. The function of the feed-through is to providean electrically conductive path from inside the enclosure to outside theenclosure, typically for several separate conductors. If the housing isformed from titanium (or other conductive material), the conductors needto be insulated from the housing, as well as from each other. Thefeed-through also needs to maintain a hermetic enclosure while passingthrough the housing body. The feed-through is typically constructed fromplatinum conductors embedded in a ceramic carrier.

Conventional assembly of the hermetic enclosure to encase theelectronics for traditional implant designs requires significant skilledlabor input and numerous operations. Housings are currently typicallymade from multiple pieces and require the device to be inverted tofacilitate connections. Such complex assembly is costly and does notfacilitate automation and reliability within the assembly process.

For example, patent document WO 2006/081361 discloses an implantablemedical device having a top and bottom shell, between which is encloseda chassis. The chassis has functional components secured to it and ishermetically sealed to one of the shells. The chassis has a feed-throughallowing input and output lines to pass into or out of the hermeticenclosure.

Furthermore, U.S. Pat. No. 6,011,993 discloses an implantable medicaldevice made from an electronic subassembly hermetically sealed in aceramic case filled with a potting material. The case is hollow with aclosed end and an open end through which the electronic subassembly isinserted while the potting material in the case is still non-cured or ina quasi-fluid state. A header, to which the electronic subassembly isconnected, is hermetically bonded to a band on the open end of the casethus hermetically sealing the medical device. The header has a pluralityof electrical feed-through terminals for connecting to the electroniccomponents on the subassembly. A particular disadvantage of such adevice is the complex, highly skilled assembly required for itsmanufacture.

Additionally, U.S. Pat. No. 4,785,827 discloses a housing assembly forelectronic circuitry that can be used subcutaneously. The housingcomprises a container and base subassemblies each including a ceramicportion and a continuous metal sealing flange. The ceramic portion ofthe container subassembly is dish like and contains a cavity withinwhich are housed electronic components. A plurality of electric leadsare brazed to and extend from the container subassembly. The sealingflanges of the container and base subassemblies are then nested togetherand welded to close and seal the housing assembly. This assemblyrequires complex skilled assembly.

SUMMARY

In accordance with one aspect of the present invention, a housing for animplantable device is disclosed. The comprises: a body portion having aplurality of walls defining a cavity in which electronic components maybe are disposed, the cavity having an opening to an exterior of thehousing on a first side of the body portion; a feed-through disposed ina first of the plurality of walls to provide an through the first wallbetween the electronic components and the exterior of the device, thefeed-through having interior and exterior connection points, theinterior and exterior connection points being accessible during assemblyof the device from the open side of the body portion; and a sealingflange operatively sealing the cavity so as to form a sealed housing.

In accordance with a second aspect of the present invention, a method offorming a sealed housing for an implantable device is disclosed. Themethod comprises: providing a body portion having a cavity for disposingelectronic components on an open side thereof; providing at least onefeed-through which provides electrical connections between theelectronic components and the exterior of the device, the feed-throughhaving interior and exterior connection points, the interior andexterior connection points being accessible from the open side of thecavity; inserting the electronic components into said cavity, and makingthe necessary electrical connections to said interior and exteriorconnection points; and attaching a sealing flange over the open side ofthe cavity so as to seal the cavity and thereby provide a sealedhousing.

BRIEF DESCRIPTION OF THE DRAWINGS

An illustrative embodiment of the present invention will be describedwith reference to the accompanying figures, in which:

FIG. 1 is a perspective view of a body portion of a housing according toone embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of the housing illustrated inFIG. 1 taken along line a-a of FIG. 1, illustrating an angledfeed-through according to one embodiment of the present invention;

FIG. 3 is a side view of a tool used to make the feed-through shown inFIG. 2, according to one embodiment;

FIG. 4 is a partial top and partial cross-sectional view of the bodyportion shown in FIG. 1 prior to insertion of the feed-through;

FIG. 5 is a cross-sectional view of the body portion of FIG. 4 takenalong line b-b of FIG. 4;

FIG. 6 is a top view of the housing, including both the body portion andthe sealing flange, according to one embodiment of the presentinvention;

FIG. 7 is a partial cross-sectional view of the housing shown in FIG. 6showing the weld positions for the sealing flange;

FIG. 8 is another partial cross-sectional view of the housing shown inFIG. 6 subsequent to overmolding;

FIG. 9 is a cross-sectional view of a feed-through configuration in thebody portion of a housing according to other embodiments of the presentinvention;

FIG. 10 is a perspective view of the feed-through configuration of FIG.9;

FIG. 11 is a cross-sectional view of the body portion with feed-throughof FIG. 9 with suitable braze wells;

FIG. 12 is a perspective view of an alternative exit configuration ofthe feed-through configuration of FIG. 9;

FIG. 13 is a partial cross-sectional view of the housing, including thebody portion shown in FIG. 9 and the sealing flange, showing the weldpositions for the sealing flange on the housing;

FIGS. 14 a and 14 b illustrate alternative feed-through attachments tothe housing according to an embodiment of the present invention;

FIG. 15 is an alternative housing having a single feed-through with acoil located at 180 degrees to the feed-through;

FIG. 16 is another alternative embodiment of a housing having a singlefeed-through with a coil located at 90 degrees to the feed-through;

FIG. 17 is a perspective view of a coil and feed-through according toone embodiment of the present invention;

FIG. 18 shows an illustrative sequence for manufacturing a combinedcoil/feed-through component; and

FIG. 19 shows an illustrative sequence of assembling the housing ofembodiments of the present invention.

DETAILED DESCRIPTION

Aspects of the present invention are generally directed to a housing foran implantable device. The housing includes a feed-through disposed in awall of the housing. The feed through includes internal and externalelectrical attachment points accessible from the same side of thehousing. As such, embodiments of the present invention allow bothelectrical and mechanical assembly to occur from one single side of thehousing.

In embodiments of the present invention, the interior and exteriorconnection points are made accessible from a single side of the housingby configuring the passage through the wall of the housing accordingly.This may illustratively be achieved by correctly angling a feed-throughthrough a wall, or by using intersecting bores, passages and undercutsin the housing for carrying the feed-through. In one embodiment, accessfrom a single side is achieved by at least part of the feed-throughbeing generally parallel to a wall of the cavity, and providing accessto the interior connection point through an undercut portion.

In embodiments of the present invention, at least one of the exteriorcomponent is integral with a feed-through conductor. In specific suchembodiments, the feed-through is connected with an exterior componentprior to its assembly or insertion into the housing. The exteriorcomponent may be selected from the group comprising a and an electrodearray. However, it would be appreciated that the exterior component mayalso or any other electrical component. As noted above, embodiments ofthe present invention are directed to methods for manufacturing animplantable medical device. One exemplary method includes the steps offorming a feed-through assembly external of a housing. Such an exemplaryfeed-through assembly includes a feed-through and an exterior componentconnected thereto. The method further comprises subsequently insertingthe feed-through assembly into the housing. Embodiments of the presentinvention are described herein primarily in connection with one type ofimplantable device, namely an implantable hearing prosthesis. Hearingprostheses in this sense include, but are not limited to, to anyacoustic or electrical auditory stimulation devices, such as cochlearimplants, middle ear implants, intra-cochlear array implants, brain stemimplants, implantable mechanical stimulators, implantable acousticdevices or any combination thereof, such as a device that electricallyand acoustically stimulates a recipient. However, it would beappreciated that embodiments of the present invention may be used inconjunction with any active implantable medical device in which it isnecessary to provide an electrical connection from the exterior of thedevice to electrical or electronic components inside the device. Itwould be appreciated that such electrical connections may be used for avariety of purposes. In certain embodiments, such electrical connectionsmay be used to connect internal electrical components with componentsoutside the device used to, for example, record incoming signals, suchas in a cardiac monitor, or for delivering electrical signals, such asin a pacemaker. Such electrical connections may also be used to connecta coil or similar device for transmission of RF power or data tointernal electrical components It should also be appreciated thatembodiments of the present invention are applicable to implantabledevices which do not perform a medical function, such as, for example,identification or location devices.

FIG. 1 is a perspective view of the body portion 20 of a housing 10 inaccordance with embodiments of the present invention. The illustrativehousing 10 includes a body portion 20 having an opening or openingsaccessible on one side of the housing, and a sealing flange 80 (notshown in this view). The housing 10 shown is for use in a cochlearimplant device, and as such is connected to a stimulation component, inthe form of electrode array 30, at one end of the body portion 20. Thehousing 10 is connected to a coil 40 at the opposite end of the bodyportion 20.

As shown in FIG. 1, the body portion 20 includes two separatefeed-throughs 50, 50′ for the connection of electrode array 20 and coil40, respectively, to an electronic assembly 70 disposed in cavity 60 ofbody portion 20. During assembly of the medical device, feed-throughs50, 50′ allow the formation of a connection between each of the coil 40and electrode array 30 with electronics assembly 70 within the cavity 60while accessing only a first one side (the top side as shown in FIG. 1)of body portion 20 in which the cavity is disposed. In other words, thefeed-through interior connection point 50 a (for making electricalconnections between the electronic assembly 70 and the interior of thefeedthrough) is accessible from the top of the body portion 20, as isthe feed-through exterior connection point 50 b (for making electricalconnections between the feed-through and the components on the exteriorof the device).

Turning to FIG. 2 where one feed-through 50 is shown in cross sectionand in greater detail, the connections 51 to the exterior of the housing10 emerge from one side of the feed-through 50, and the connections 52to the interior of the housing 10 emerge from the other side.

In the present embodiment and as shown in particular in FIG. 2, thefeed-throughs 50, 50′ are angled through a wall of the cavity 60, fromthe top side 20 a of the body portion 20 to the bottom side 20 b, toallow assembly from one side of the housing 10 while still creating ahermetic enclosure for the electrical assembly 70. The angling alsoallows the feed-throughs 50, 50′ to be sufficiently long to form aneffective hermetic seal, while minimizing the overall implant thickness.The length of the hermetic seal is may be important for embodiments inwhich the conductor is sealed in ceramic.

Standard biocompatible materials may be used for the various componentsof the device. Ideally, the body portion 20 and sealing flange 80 aremade from a metal such as titanium, while the coil 40, electrodecontacts and electrode wires are made from platinum or platinum/indiumalloy, and the feed-throughs 50, 50′ are made from an alumina basedceramic. Other biocompatible materials may however be used. For example,the body portion 20 and sealing flange 80 could be made from stainlesssteel, while the coil 40 is made from gold and the feed-through 50 ismade from a zirconia based ceramic.

It certain embodiments of the present invention cavity 60 is shallow indepth relative to its surface area. This facilitates easy assembly, asit provides easy access for manually or automated operations. Further,it assists in minimizing the thickness of the housing 10.

Typically, the feed-throughs 50, 50′ and associated components 30, 40constrain the thickness of the implant. The angled feed-through 50, 50′,combined with the single sided body portion 20 assists in allowing athinner implant to be achieved. For example, for a specific cochlearimplant with housing dimensions of approximately 20 mm×30 mm, athickness of approximately 2.5 mm is achievable. An implant of thisthickness is may be beneficial for implantation in children. While theskull of even small children is more than large enough in area toaccommodate an implant, the curvature is much greater than for an adult,and accordingly a thickness of the order of approximately 6 mm (typicalfor current implants) results in a discernable bump under the skin.

Despite the reduced thickness realized through embodiments of thepresent invention, such embodiments still provide significant materialand strength in the housing 10. For example, as discussed above, incertain embodiments the body portion 20 and sealing flange 80 may beformed from titanium. In such embodiments, there are a number of regionsof the body portion 20 where the titanium is the full thickness of thebody portion 20, shown for example in FIG. 2, and the body portion 20will be rigidly attached to the titanium sealing flange 80 by laserwelding (as will be further described below). This makes theconstruction extremely robust and results in high resistance to impact.

An angled feed-through shape as in the present embodiment can be madesuch that it can still be molded on a simple split tool 55 as shown inFIG. 3. The construction of the ceramic feed-through is otherwiseconventional, and will not be further described as it is well understoodby those skilled in the art. As is conventional, the ceramic may bebrazed to the titanium body portion 20, using any suitable technique toestablish a suitable seal. The brazing could be controlled usingcapillary brazing, for example as disclosed in Australian applicationNo. 2005907265, the disclosure of which is hereby incorporated byreference herein. Suitable braze reservoirs 53, 54 are constructed inthe body portion 20, as shown in FIGS. 4 and 5.

It will be appreciated that embodiments of the present invention may beapplied to arrangements with a single feed-through, or to arrangementshaving two or more feed-throughs.

FIG. 6 shows a top view of the housing 10 of FIG. 1 with the sealingflange 80 (or top shell) attached. FIG. 7 shows a more detailscross-sectional view of this arrangement. The top shell 80 is may beattached to the body portion 20 using laser welding at a number ofpoints 85, 90 on the body portion 20. In particular, welding isperformed around the outside of the body portion 20 indicated byreference 90, along with additional welds across the width of the bodyportion 20, as indicated by reference 85, to seal the central hermeticcavity 60.

Note that the channels 58 in certain embodiments are not sealed into thehermetic space, but are protected by the shell 80 and sealed by thesilicone material as part of the overmolding process. Final overmoldingis achieved using vacuum silicone molding similar to existing implants,to produce the final sealed housing 100 as shown in FIG. 8.

FIGS. 9 to 13 illustrate an alternative embodiment of the housing, inwhich the housing wall is undercut. As can be seen in FIGS. 9 and 10,the feed-through 150 is generally parallel to the wall of the cavity 60,with the feed-through entry 125 for connectors being accessible from thetop of the housing 120, as is the feed-through exit 151. The exit 151 ofthe feed-through 150 is formed in the housing wall 120 as an undercutportion to allow assembly from one side while still creating a hermeticenclosure for the electrical assembly (not shown in this view). Theconductors 155 may be simply bent, as can be seen in FIG. 9, so as topass into the interior of the housing 120.

In certain such embodiments, cavity 60 may be relatively shallowrelative to the surface area. This facilitates easy assembly, as itprovides easy access for manually or automated operations. Further, itassists in minimizing the thickness of the housing 120. As noted, thefeed-through structure may be a constraint on how thin the implant as awhole may be manufactured. The vertical feed-through 150 used in thissecond implementation, combined with a single sided housing 120, assistsin allowing a thinner implant to be achieved. Similar to the embodimentsdescribed above, significant material and strength in the housing 120remains in the implementation of FIGS. 9-13. The strength according tothese embodiments may be further improved by adding one or more pillars152 to the undercut 151 shown in FIG. 10. This results in an undercut151 as shown in FIG. 12.

An undercut 151 to the housing 120 can be machined from solid titaniumusing conventional techniques, and will not be further described as itis well understood by those skilled in the art. As is conventional, theceramic feed-through 150 may be brazed to the titanium housing, usingany suitable technique to establish a seal. Suitable braze reservoirs153, 154 are shown in FIG. 11.

FIG. 13 illustrates feed-through 150 positioned in the housing 120 afterbrazing and sealing. Sealing flange 180 is attached at welding points185, 190 to seal the enclosure after the electrical connections arecompleted. The assembly can then be overmolded, as described above.

FIGS. 14 a and 14 b illustrate two alternative feed-through attachmentsto the housing. In FIG. 14 a, two coils 40′ are shown, requiring fourexterior connection points 41′ to the housing. In FIG. 14 b, one coil 40is used, requiring only two exterior connection points 41 to thehousing.

FIGS. 15 and 16 illustrate two alternative arrangements in which thecoil 40 and the electrode array 30 can utilize the same feed-through 50.FIG. 15 illustrates coil 40 at the opposite side of the body portion 20to the feed-through 50 with the coil connector 44 being contained in achannel 22 around the perimeter of the body portion 20 and fed to thefeed-through 50. This method requires longer wiring and slightlyincreased weld complexity to the embodiments described above having twofeed-throughs. FIG. 16 illustrates the coil 40 at ninety degrees to thefeed-through 50. Again, this construction requires slightly increasedwiring and weld complexity, but may be suitable for particularapplications.

To further simplify assembly of the housing in accordance any of theabove embodiments, the coil 40 and coil feed-through 50′ can beassembled together, prior to insertion into, or assembly of, thehousing. The coil 40 generally is made up of a carrier and an electricalconductor embedded in the carrier. The electrical conductor may beconveniently formed by punching it from a foil, which could be made forexample from platinum, with a multi coil structure being formed byfurther folding the punched foil. Such a foil coil 40 may have a shapeother than circular, and the technique may be implemented withconnectors other than coils, e.g. electrode arrays.

In certain embodiments, a powder injection molding (PIM) feed-throughconcept may be implemented. In such embodiments, the PIM feed-throughallows feed-throughs to be molded around a platinum pin, as disclosed inAustralian patent application No. 20060141861, the disclosure of whichis hereby incorporated by reference herein. Using both the foil coil 40′and the PIM feed-through technique, the coil 40 may be moulded straightonto the feed-through 50′ as shown in FIG. 17, as opposed to asubsequent coil attachment process as shown in FIGS. 14 a and 14 b. Thisis performed as part of feed-through manufacture. Hence, in such anembodiment, the feed-through manufacturing process results in a combinedcoil-feed-through sub assembly. This sub assembly is brazed to thehousing 10 as in other embodiments.

Referring to FIG. 18, a suitable process for forming the combinedfeed-through assembly is described. The coil 40 is first stamped from afoil of suitable metal, as indicated by step 60. Ceramic powder is thenmolded around the protruding legs of the foil coil 40, for example usinga powder injection molding process, indicated as step 61. The ceramic isthen subjected to the regular processes of ceramic manufacture, forexample de-binding and sintering, to form a finished sub-assembly atstep 62. It will be appreciated that as the coil 40 is typically formedfrom a platinum or platinum alloy, it can be readily subjected to theheating processes necessary for the ceramic.

In other embodiments the coil 40 may be attached to the feed-through 50′after each have been separately formed. The coil 40 may be formed usinga foil coil, for example as disclosed in Australian Patent ApplicationNo. 2006905752, the disclosure of which is hereby incorporated byreference herein, or as a conventional coil, and then attached viawelding/crimping or other suitable method. This coil/feed-throughassembly could equally be used by any connector(s) and connectorfeed-through. As described above, the ceramic feed-through 50′ may thenbe brazed to the titanium housing 10, using any suitable technique toestablish a suitable seal.

Connections from the feed-through connection 50 b to the electricalassembly 70 may be made using any available technologies such assoldering. However, in certain embodiments such connections may be madeusing an easily automated technique such as resistance welding or wirebonding.

A magnet is typically used to provide an attractive force to position anexternal coil which forms a transcutaneous link to the implant coil. Tofurther simplify assembly, the magnet may be contained in the housingrather than with the exterior coil, for example as disclosed inpreviously referenced Australian Patent Application No. 2006905752.

A suitable process for assembling a housing, such as that illustrated inFIG. 1 or FIG. 9, will now be described with reference to FIG. 19. Itwill be appreciated that is merely illustrative and the process may varydepending upon the device being manufactured.

At step 70, the body portion 20 and sealing flange 80 are formed intitanium, using conventional processes. A dispenser applies braze pasteinto the previously described reservoirs 53, 54 in the body portion 20.A “pick and place” machine inserts the feed-throughs 50, 50′ into thecavities in the body portion 20. Preferably, the feed-through 50′ isattached to the coil 40 prior to insertion into the cavity, forming asub-assembly, per the method described above.

At step 71, the assembly is then placed into a furnace to melt the brazeand seal the feed-throughs 50, 50′ to the body portion 20. The “pick andplace” machine then positions the electrical assembly 70 in the bodyportion 20, together with the magnet(s) noted above, and places theelectrode array 30 (and coil 40 if not part of a sub-assembly) intoposition. A robotic welder then makes the necessary electricalconnections.

In the case of the second embodiment shown in FIGS. 9 to 13, thefeed-through 150 can be inserted vertically into the correspondingcavity, with otherwise similar processes.

At step 72, the “pick and place” machine places the top shell 80 intoposition. It is noted that the shell 80 covers the whole top surface ofthe body portion 20, but is welded so as to leave the feed-throughconnections outside the sealed cavity 60. The shell 80 accordingly actsas a sealing flange for the cavity 60 in the body portion 20. A roboticlaser welder can be used to affix the top shell 80.

Finally, the housing 10 is subjected to an overmold procedure in which asealing material encases the entire assembly. The sealing material maybe any suitable biocompatible material, for example a silicone polymer.The assembly, as shown at step 74, is then complete.

As noted above, it would be understood that embodiments of the presentinvention are applicable to any type of medical device in which afeed-through arrangement is utilized to electrically connect componentswithin a housing to components exterior to the housing. It will befurther understood that the method described in FIG. 18 may be appliedto differently designed housings, using different types offeed-throughs. Variations and additions, for example to the processesfor forming and affixing the feed-through sub-assembly, are possiblewithin the scope of the present invention.

The foregoing discussion is considered as illustrative only of theprinciples of the invention. Furthermore, since numerous modificationsand changes will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be used, falling within the scope of the invention.

characteristics may be combined in any suitable manner in one or morecombinations.

The invention described and claimed herein is not to be limited in scopeby the specific embodiments herein disclosed, since these embodimentsare intended as illustrations, and not limitations, of several aspectsof the invention. Any equivalent embodiments are intended to be withinthe scope of this invention. Indeed, various modifications of theinvention in addition to those shown and described herein will becomeapparent to those skilled in the art from the foregoing description.Such modifications are also intended to fall within the scope of theappended claims. All patents and publications discussed herein areincorporated in their entirety by reference thereto.

1. A housing for an implantable device, the housing comprising: a bodyportion having a plurality of walls defining a cavity in whichelectronic components may be disposed, the cavity having an opening toan exterior of the housing on a first side of the body portion; afeed-through disposed in a first of the plurality of walls to provide anelectrical connection through the first wall between the electroniccomponents and the exterior of the device, the feed-through havinginterior and exterior connection points, accessible during assembly ofthe device from the first side of the body portion; and a sealing flangeoperatively sealing the cavity so as to form a sealed housing.
 2. Thehousing according to claim 1, wherein the cavity has shallow depthrelative to the area defined by the cavity opening.
 3. The housingaccording to claim 1, wherein at least part of the feed through isgenerally parallel to the first wall of the cavity, and wherein thefirst wall comprises: an undercut portion adjoining the cavity so that,the interior connection is accessible during manufacture through thecavity.
 4. The housing according to claim 1, wherein at least part ofthe feed-through passes at an angle through the first wall of thecavity.
 5. The housing according to claim 1, further comprising: asecond feed-through disposed in one of said plurality of walls andhaving interior and exterior connection points accessible duringassembly of the device from the first side of the body portion.
 6. Thehousing according to claim 5, wherein the housing contains components ofan implantable hearing prosthesis comprising a stimulation component anda coil, and wherein at least one of the exterior connection points ofthe feed-through disposed in the first wall is connectable to the coil,and wherein at least one of the exterior connection points of the secondfeed-through is connectable to the stimulation component.
 7. The housingaccording to claim 1, wherein at least one of the external electricalconnection points of the feed-through is retained in a channel on asurface of the first side of the body portion.
 8. The housing accordingto claim 1, wherein at least one of the exterior connection points isintegral with the feed-through.
 9. (canceled)
 10. The housing accordingto claim 1, wherein one or more of the exterior connection points areconnectable to exterior components selected from the group comprising acoil, an electrode array, or an electrical connection component. 11.(canceled)
 12. A method of forming a sealed housing for an implantabledevice comprising: providing a body portion having a plurality of wallsdefining cavity, the cavity having an opening to an exterior of thehousing on a first side of the body portion; inserting the electroniccomponents into said cavity; positioning at least one feed-through in afirst of the plurality of walls to provide an electrical connectionthrough the first wall between the electrical components and theexterior of the device, the feed-through having interior and exteriorconnection points accessible during manufacture of the device from thefirst side of the body portion; and attaching a sealing flange over theopening of the cavity so as to form a sealed housing.
 13. The methodaccording to claim 12, wherein providing the body portion furthercomprises: providing a body portion having a cavity that has a shallowdepth relative to the area defined by the cavity opening.
 14. The methodaccording to claim 12, wherein the first wall comprises an undercutportion adjoining the cavity, and wherein positioning at least onefeed-through in the first wall further comprises: positioning thefeed-through such that at least a part of the feed-through is generallyparallel to a wall of the cavity and such that the interior connectionpoints are accessible in the undercut portion from the cavity duringassembly.
 15. The method according to claim 12, wherein positioning atleast one feed-through in the first wall further comprises: positioningthe feed-through such that at least a part of the feed-through passes atan angle through the first wall of the cavity.
 16. The method accordingto claim 12, further comprising: positioning a second feed-through inone of the plurality of walls of the cavity, the second feed-throughhaving interior and exterior connection points accessible duringassembly of the device from the first side of the body portion.
 17. Themethod according to claim 16, wherein the implantable device is ahearing prosthesis comprising a coil and a stimulation component, andwherein the method further comprises: connecting at least one of theexterior connection points of the feed-through disposed in the firstwall to the coil, and connecting at least one of the exterior connectionpoints of the second feed-through to the stimulation component.
 18. Themethod according to claim 12, further comprising: connecting one or moreof the exterior connection points of the feed-through to an exteriorcomponent prior to positioning the feed-through into the body portion.19. The method according to claim 12, further comprising: forming afeed-through assembly exterior to the housing, the feed-through assemblyincluding the feed-through and an exterior component connected to one ormore of the exterior connection points; and inserting the feed-throughassembly into the housing.
 20. The method according to claim 18, whereinthe exterior component is selected from the group comprising a coil, anelectrode array, or an electrical connection component.
 21. The methodaccording to claim 20, wherein the coil, electrode array or electricalconnection component includes a conductor, and wherein the methodfurther comprises: forming the conductor by stamping from a metal foil.22. The method according to claim 12, metal, and wherein thefeed-through is formed of ceramic, and wherein the method furthercomprising: affixing the ceramic feed-through to the first wall via abrazing process. 23-29. (canceled)
 30. The housing according to claim 5,wherein the second feed-through is disposed in second of said pluralityof walls of the body portion.